Shock mount



Oct. 30, 1951 D. BACON ET AL 2,572,969

SHOCK MOUNT Filed Sept. 22, 1948 2 SHEETSSHEET 1 27 INVENTORS DHvlDLBHcoN James E. MeLoueHLm ATTORN EY Oct. 30, 1951 D, BACON ET AL 2,572,969

SHOCK MOUNT Filed Sept. 22, 1948 2 SHEETS-SHEET 2 .v unnnnnun nlnrnunm'nman,"

5 I I I i INVENTORS DnvmLBHcoN JR Mes E. McLo'ue'H u N ATTO R N EY Patented Oct. 30, 1951 UNIT ED STATES PATENT O'FliCEi SHOCK MOUNT David. L. Bacon, North Haven, and; James E.

McLoughlin, New Haven, ,Con-n., assignors to The. Soundscriber Corporation, New Haven, Conn, a corporation of Connecticut Application-September 22, 1948, Serial No. 50,618

2 Claims.

This invention relates to shock absorbing supports, and more particularly to a shock mount for dictating machines and other instruments of a sensitiveor vibratory nature.

One object of this invention is to provide. a device of the above nature which willefiectively prevent shocks from being transmitted in any direction from the surface upon which the mount is supported to an instrument on said mount, or conversely from avibratoryinstrument .to a supporting. surface- Another object. is t provide a device of the abovenaturehaving shock, absorbing elements which are so arranged .as to permit a very. com-- pactconstruction, whereby said mount will occupy. little. space, and will be. inconspicuous...

A further object is, to provide a device. of, the above. nature which Willbe simple in construe.- tion, inexpensive. to manufacture, .easy to install and, manipulate, ornamental in appearance, and very eflicient and durable in use.

With these and other objects inview, there has been illustrated on the accompanying drawing one form in which the invention may conveniently be embodied in practice.

In the drawings,

Fig. 1 is a side elevation of the improved shock mount, showing aninstrument thereon in broken lines.

Fig. 2 is a bottom view of the mount, taken on the line 2-2 of Fig. 1.

Fig. 3 is a cross-.sectionalview of the same, taken on the line 33 of Fig. 2, showing the parts in a neutral and unloaded condition.

Fig. 4- is: at cross-sectionallvievw ofr the same, taken on the line 4-4 of Fig. 2.:

Fig. 5 is a cross sectional View on an enlarged scale of a; portion of the shock mount, showing the parts in the position they would assume-when loaded-and-showing the actionof the: balls in absorbing lateral shocks. 7

Fig. 6-is-a cross-sectional view similarito a portion of Fig. 4, on an enlarged scale, but showing the mount in a loaded and laterally displaced condition.

Referring now to the drawings, in which like reference numerals denote corresponding parts throughout the several views, the numeral l indicates generally the improved shock mount, and the letter I indicates an instrument thereon. The mount l0 comprises a rectangular lower plate II and a rectangular inner plate l2, each of which is provided respectively with a plurality of circular recesses I3, l4 formed by embossing the plate material adjacent the respective corners of the plates.

The plates; l l 2.- may- -beof identical form, but willrbe reversed in position so that the: recesses I3; [4. are adapted to confine a plurality of 1 balls I5 ofjany suitable." material, suchlassteel, glass, or' rubber. It will be-notedthat the plates H, 12 are flat excepting in the area of therecesses I3; M, whereby saidplates'wilhhave a small degree ofinherent flexibility This-flexibility; will permit the recesses l3, l4 andi theeballss'l-5.-to-be held. always in firm engagement the-load. imposed upon the; shoclemount, thus contributing to the stability; of themounta-ndavoiding loose ness or play therein in theseventthatthesurface supporting the mountis not perfectly flat, or if one of the balls l5 should'be slightly displaced orout of phase with-the otherzba'lls.v

In order. torenderx'the. balls. l5: self-centering whenv in use, the recesses; l 3;. Hi are'zeach pro:- vided. with an inner surfaced 5a: which is: spherical in curvature, and-informed. on a: radius greater than theeradiuszofathe-balls l 5. A .steep periph eral'wall [5b is. formed inangularrrelati'on'to each of the curved surfaces ltd, thuslpositively limiting .the movementof the ballsxzl 5:

It has been ioundndesirable inpractice to form the: innerxsurfaceszifia: on a. verticalztradius which is? approximately: six.- times the diameter of. the balls: l5; whilezthe horizontal diameter of the recesseszl 3, l4= will be approximatelysone'and:one+ half times. the diameteriof .theba'lls I 5.

The:. surfaces. It'mnmay if: desired, be formed on an elliptical. curvature, whereby the shock mountzmay berma'de. very. sensitivev in onez'horiz-L zontal direction; while. resisting displacement moreafirmly in another horizontal direction.

In orderto prevent'texcessive-separation ofthe plates H, 12'. during.- handling, and: consequent IOSSZOfth'B ball l5, provision is made of a' pair of end brackets l6 which are U-shaped in cross section andare secured by screws I 1 to central portions of opposite ends-- of the-lower plate "I l in such apcsition as-toz extend in spaced relation over the end-edges of the-'inner'platel 2.

The end brackets [6 will thus permit free action of the ball bearings 15. Said brackets are provided, however, with resilient bumper pad IS on their inner surfaces in order to cushion impact by the inner plate l2 in the event that an excessive lateral shock should be applied to the mount.

A rectangular top plate l9, which is somewhat larger than the inner plate [2, is supported upon said inner plate by means of a plurality of sponge rubber pads 29, which rest upon the inner plate in inwardly offset relation to the respective ball recesses l 4. The top plate 19 is provided with 3 upwardly struck bosses 2| which serve as seats for the sponge rubber pads 20, and in which said pads are preferably secured by means of cement 2Ia.

The top plate I9 is held in assembled relation to the inner plate I2 by means of a pair of headed retainer screws 22 disposed in enlarged apertures 23 (Fig. 6), in the top plate I9 and firmly secured in apertures in the inner plate I2 by pairs of nuts 24. The retainer screws 22 are also provided with washers 25 which will prevent the heads of said screws from passing through the apertures 23, and rubber sleeves 26 which will serve as cushions in the event that the edges of the apertures 23 should be shifted laterally against said screws.

By means of this construction, the weight of an instrument resting upon the top plate I9 will be resiliently supported by the sponge rubber pads 20, and the retainer screws 22 will not interfere with the resilient action of said pads.

The material and the proportions of the pads 20 will preferably be such that said pads will have at least one-half of their uncompressed thickness when supporting the normal load which the top plate I9 is intended to carry, whereby said pads will function efficiently to absorb vertical shocks.

The top plate IQis provided with a depending peripheral flange 21 which will protect the bearings I5 against dust and will conceal the parts below the top plate l9.

Operation In operation, the shock mount III will be found useful to support a dictating machine or other sensitive instrument upon any suitable horizontal surface such as a desk. If desired, the mount I may be built into the instrument so as to be a part thereof. The bosses formed by the recesses I3 in the lower plate II will, of course, serve as feet for supporting the mount.

The shock mount III will protect the instrument I mounted thereon against substantially any shock which would normally be transmitted thereto by the supporting surface. Any sudden horizontal shock imparted to the lower plate II, will result merely in rolling of the balls I in the recesses I3, I4, so that the inner plate I2 and the top plate I9 will be permitted to remain relatively stationary, and the instrument I will be protected against horizontal impulses. The large radius of curvature of the recesses I3, I4 will provide the shock mount with a natural period of horizontal oscillation which is much longer than the period of any horizontal vibration that would ordinarily be encountered in a stationary build- Any vertical shocks imparted to the lower plate II by the supporting surface will, of course, be

absorbed by the resilient pads 20, thereby substantially eliminating sudden vertical movement of the instrument I.

, One advantage of the improved shock mount herein disclosed is that it is very compact and inconspicuous.

While there has been disclosed in this specification one form in which the invention may be embodied in practice, it is to be understood that this form is shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosure, but may be modified and embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new and for which it is desired to secure Letters Patent is:

1. In a shock mount, a pair of plates, devices between said plates for supporting one of said plates upon the other for substantially free lateral movement of limited extent, and means for retaining said plates in loosely assembled relation, said retaining means comprising a pair of U-shaped end brackets secured respectively to opposite ends of one of said plates and extending in spaced relation around the end of the other of said plates, whereby said end brackets will not interfere with free action of said supporting devices.

2. In a shock mount, a bottom plate, an inner plate, balls between outer portions of said bottom plate and said inner plate for supporting the latter for free lateral movement of limited extent, said balls being confined by recesses in one of said lower and inner plates, said recesses having inner surfaces which are curved on a radius greater than the radii of the balls, a top plate resiliently carried upon said inner plate, and means comprising a pair of retainer screws secured in said inner plate and extending outwardly through enlarged apertures in said top plate for retaining said inner and top plates in loosely assembled relation, said bottom plate and said inner plate each having a flexible central portion, whereby a load on said top plate will hold said bottom and said inner plates in firm engagement with said balls despite small irregularities in the surface supporting said shock mount or in the position of said balls.

DAVID L. BACON. JAMES E. McLOUGI-ILIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,414,506 Bowen Jan. 21, 1947 2,437,206 Naher Mar. 2, 1948 2,441,509 Robinson May 11, 1948 

